A Prolog variant with guarded clause s and committed-choice nondeterminism ( don't-care nondeterminism ) by Ehud "Udi" Shapiro, Yale shapiro-ehud@yale.edu . A subset has been implemented, but not the full language.
See also Mandala .
["Concurrent Prolog: Collected Papers", E. Shapiro, V.1-2, MIT Press 1987].
(1994-11-30)